bug fix FractionalMaxPool2d (random_samples dimensions) (#70031)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/70031
Test Plan: Imported from OSS
Reviewed By: ejguan
Differential Revision: D33200618
Pulled By: george-qi
fbshipit-source-id: 142f224c2cab1008d2d4e9ed333697a92d2d42db
